剑河M5.5地震前地磁异常特征分析  

Analysis of geomagnetic anomalies before the Jianhe M5.5 earthquake

作　　者：郭明瑞[1] 胡久常[1] 王锡娇[1] 马龙 王桂丹[1] 郑在壮[1] Guo Mingrui;Hu Jiuchang;Wang Xijiao;Ma Long;Wang Guidan;Zheng Zaizhuang(Hainan Earthquake Agency,Haikou 570203,China)

机构地区：[1]海南省地震局,海口570203

出　　处：《地震科学进展》2020年第5期12-17,共6页Progress in Earthquake Sciences

摘　　要：地磁垂直分量Z日变幅逐日比是基于变化磁场在地球电导率的作用下会产生一个与变化磁场相反的感应磁场,该感应磁场不仅包含了外空磁场的信息,还包含了地下电导率的信息。因此,相对于地磁场其他成分来说,Z分量更多地反映了地下活动的变化,逐日比是利用前后两日地磁Z分量日变幅相比来提取该异常现象。本文利用华南部分地磁台站数据进行逐日比计算,结果显示2014年12月22日出现高值异常,于异常日99天后发生地震。双低点是地磁Z分量出现相位和幅度变化,从正常的V字型变为W型,改变了正常的日变形态。在地震前57天,贵州、广西、海南、湖南等大部分地区出现双低点异常,震中位于低点异常分界线附近,地磁低点位移的出现与地震的孕育和发生相关。本文结合逐日比和双低点来预测地震,可提高其可信度。Daily variation ratio of geomagnetic vertical component(Z)is important in the study of earthquake precursor analysis.The ariation magnetic field makes an induced magnetic field because of the earth conductivity,and the induced magnetic field includes information from outer magnetic field and underground electrical conductivity,so the geomagnetic field Z component reflects more changes of underground activity than other components.The paper processes the geomagnetic vertical component data of partial geomagnetism of south China stations located in the study area by using the ratio of daily variation amplitude method.The results show here existed high value anomaly of load on December 22,2014,and the earthquake occurred 99 days after the anomaly date.The double low point is the phase and amplitude change of the geomagnetic Z component,from the normal V-shape to the W-type.To change the normal diurnal pattern,57 days before the earthquake,most regions such as Guizhou,Guangxi,Hainan,Hunan a double low anomalies.Near the epicenter is located in the low anomaly dividing line,the emergence of geomagnetic low-value displacement associated with earthquake gestation and occurrence.This paper combines daily ratio and double low point to predict earthquake,which can improve its credibility.

关 键 词：逐日比 地磁Z分量 低点位移 地磁日变 

分 类 号：P315.721[天文地球—地震学]